Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone

B. Papp, A. Enyedi, K. Paszty, T. Kovacs, B. Sarkadi, G. Gardos, C. Magnier, F. Wuytack, J. Enouf

Research output: Contribution to journalArticle

86 Citations (Scopus)

Abstract

Phosphorylation, immunoblotting, limited proteolysis and drug-sensitivity analysis were used to characterize the sarcoendoplasmic-reticulum Ca2+ ATPases in a variety of human cell types. In platelets, several megakaryoblastoid and lymphoblastoid cell lines two distinct autophosphorylated forms of these ATPases with molecular mass of 100 and 97 kDa could be observed, whereas in several other cell types the 97 kDa form was absent. On immunoblots the 97 kDa species was specifically recognized by an inhibitory monoclonal antibody raised against the Ca2+ pump of platelet internal membranes, yielded on trypsinolysis a major fragment of 80 kDa, exhibited a distinct electrophoretic migration pattern as compared with the skeletal-, cardiac- and smooth-muscle Ca2+ pumps, and its autophosphorylation was strongly inhibited by the Ca2+-mobilizing agent 2,5-di-(t-butyl)-1,4-benzohydroquinone (tBHQ). The 100 kDa species reacted with an antibody specific for the cardiac- and smooth-muscle Ca2+ pumps, yielded on trypsinolysis fragments of 55 and 35 kDa, and its autophosphorylation was much less sensitive to tBHQ inhibition. These findings indicate the simultaneous presence of two different endoplasmic-reticulum Ca2+ pumps in a variety of human cell types, and may explain the previously observed differences in the Ca2+-handling characteristics of different intracellular Ca2+ pools and cell types.

Original languageEnglish
Pages (from-to)297-302
Number of pages6
JournalBiochemical Journal
Volume288
Issue number1
DOIs
Publication statusPublished - Jan 1 1992

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Simultaneous presence of two distinct endoplasmic-reticulum-type calcium-pump isoforms in human cells. Characterization by radio-immunoblotting and inhibition by 2,5-di-(t-butyl)-1,4-benzohydroquinone'. Together they form a unique fingerprint.

  • Cite this